In high bandwidth networks such as fiber optic networks, lower bandwidth services such as voice communications are aggregated and carried over a single fiber optic link. However, because the aggregated data can have different destinations some mechanism for switching the aggregated components is required. Switching can be performed at different levels of aggregation.
Current switching is accomplished in a synchronous manner. Signals are routed to a cross-connect or similar switching device that switch and route signals at some predetermined granularity level, for example, byte by byte. Synchronous switching in a cross-connect is a logically straight forward method for switching. However, because data flow between network nodes is not necessarily consistent, switching bandwidth may not be used optimally in a synchronous cross-connect. One source of data may use all available bandwidth while a second source of data may transmit data sporadically.
In order to support data sources that transmit at or near peak bandwidth, cross-connects are designed to provide the peak bandwidth to all data sources because specific data rates of specific data sources are not known when the cross-connect is designed. As a result, all data paths through the cross-connect provide the peak bandwidth, which may not be consumed by some or even most of the data sources.
A further disadvantage of synchronous switching architectures is that centralized switching control and interconnections grow exponentially as the input/output paths grow. Therefore, large switching architectures are complex and require complex control algorithms and techniques.